1. Field of the Invention
This invention relates generally to a mobile radio telephone and, more particularly, to a mobile telephone of modular design comprising a main unit and a detachable accessory unit adaptable to a variety of specialized capabilities.
2. Description of the Prior Art
It is known to provide radio telephones comprised of separate modules. For example, in European Application No. EP 521,609 published Jan. 7, 1993, entitled "Radio Phone Composable of Separate Modules", a radio telephone capable of dual-mode operation comprises a basic module including circuitry common to the operation of the telephone in both modes, a first supplementary module including circuitry for processing signals characteristic of a first mode of operation, and a second supplementary module including circuitry for processing signals characteristic of a second mode of operation. With this construction, at least one of the modules is detachably coupled to the basic module so that the telephone is operable in the first and/or second modes according to which of the first and second supplementary modules is coupled to the basic module.
Although this is a desirable arrangement, known systems do have a number of drawbacks. For example, in the instance of a vibrating module being fitted to the base phone, this would not be desirable to customers who does not need it, yet they would be required to pay for such a module. Undesirably, also, such a module also makes the phone heavier. Further, if the vibrating module is fitted inside the phone, customers would be required to visit a repair shop to have the module installed, adding to the expense. Yet again, if the vibrating module is part of the battery pack, it would be necessary to dispose of it with the battery when the battery fails, again being costly for the user.
It was in light of the foregoing that the present invention was conceived and has now been reduced to practice.